If you would like to add 6 inches of soil to the area, take the total square feet area, multiply by .5 (half a foot) then divide by 27 to get square yards. B1 = oxygen diluted level in the dilution water at t=0 = B2 = oxygen diluted level in the dilution water at t=5 How much sod or soil do I need? When a soil test of the lawn is not available, Table 5 can be used as a guide for lawn fertilization. Price: Sod Estimate: For a more detailed guide on sod installation, check out This Old Houses page.